1. Field of the Invention
The present invention relates to a wireless communication device, for example, a wireless communication device usable in a contactless communication system such as an RFID (Radio Frequency Identification) system and an article including the same.
2. Description of the Related Art
To date, an IC tag described in Japanese Unexamined Patent Application Publication No. 2004-126750 has been known as an IC tag used in a contactless communication system. Since the IC tag of this type has an antenna and an IC module that are directly connected to each other, the impedance of the antenna itself needs to be set to correspond to the complex conjugate of the impedance of the IC module. Accordingly, if there are different ICs or different shapes for the antenna, the antenna of a contactless IC tag needs to be designed according to specific characteristics of the IC or the shape of the antenna. In addition, evaluation is generally performed by using a measurement system based on 50Ω. These factors cause a problem of a very high degree of design difficulty. Moreover, for example, if a metal object is disposed adjacent to the antenna, the impedance of the antenna itself changes, and the frequency characteristic of the IC tag is thus prone to change.